Heat treatment apparatus and method for heating substrate by light irradiation

Abstract

In light-irradiation heating with a total irradiation time of one second or less, two-stage irradiation is performed, including a first stage of light irradiation of a semiconductor wafer, which irradiation produces an output waveform that reaches a peak at a given emission output; and a second stage of supplemental light irradiation of the semiconductor wafer, which irradiation is started after the peak, producing an emission output smaller than the above given emission output. The emission output in the second stage is two thirds or less than the above given emission output at the peak. The first-stage light-irradiation time is between 0.1 and 10 milliseconds, and the second-stage light-irradiation time is 5 milliseconds or more. This allows the temperature of the semiconductor wafer even at a somewhat greater depth below the surface to be raised to some extent while allowing the surface temperature to be maintained at a generally constant processing temperature.

1. A heat treatment apparatus for heating a substrate by light irradiation of the substrate, the apparatus comprising:
 a holder for holding a substrate; 
 a light irradiation part for irradiating the substrate held by said holder with light; 
 a light-emission controller for controlling an emission output of said light irradiation part, 
 said light-emission controller being configured to control an emission output of said light irradiation part in such a manner that, within a time range that a total time of light irradiation is one second or less, light irradiation of a substrate is performed, producing an output waveform that reaches a peak at a first emission output, and then after said peak, supplemental light irradiation of the substrate is performed, producing an emission output smaller than said first emission output, wherein 
 said light-emission controller is configured to control the emission output of said light irradiation part in such a manner that said supplemental light irradiation is started after said peak and when the emission output becomes two thirds or less said first emission output. 
 
     
     
       2. The heat treatment apparatus according to  claim 1 , wherein
 a light irradiation time before the start of said supplemental light irradiation is between 0.1 and 10 milliseconds. 
 
     
     
       3. The heat treatment apparatus according to  claim 2 , wherein
 said supplemental light irradiation is performed for 5 milliseconds or more. 
 
     
     
       4. The heat treatment apparatus according to  claim 1 , wherein
 said light irradiation part includes a flash lamp, and 
 said light-emission controller is configured to exercise chopper control over light emission from the flash lamp.